The present invention relates to a disposable hygiene article comprising a melt-spun elastic fiber, in particular a diaper. Furthermore, the present invention relates to a process for preparing a disposable hygiene article comprising the steps of providing a melt-spun elastic fiber and applying the melt-spun elastic fiber to a disposable hygiene article or a part which is used to prepare the disposable hygiene article; as well as the use of a melt-spun elastic fiber in a preparation process for preparing a disposable hygiene article.
Disposable hygiene articles are increasingly used because of their convenience. A disposable diaper, for example, varies from baby diaper to adult diaper in its size, usability and shape. Recently, a pull-up type in a form of short pants is more widely used than a simple straight diaper. An elastic body is used for this type of disposable diaper for elasticity and wearing comfort. A rubber-based elastic yarn or a polyurethane-based dry spun spandex fiber is widely used, mainly on the flap part of the legs and the cuff part, and stretchable nonwoven fabric is used on the side panels and on the waist band. The flap part of the legs and the cuff part have impact on the functionality and wearing comfort of diapers, depending on the physical properties of elastic yarns used. And diaper manufacturers are now making ceaseless efforts to develop an elastic yarn having improved flexibility as well as wearing comfort in order to produce a higher value-added diaper.
The cuff part in disposable diapers primarily prevents the liquid discharge from leaking out and the flap part of the legs secondly prevents leakage of the liquid discharge. These two parts have direct influence on wearing comfort as they are closely attached to the body. If the elastic yarn used is too tight, it leads to deterioration in wearing comfort, and causing red mark around the legs, whereas if too loose, the liquid discharge would leak out of the diaper. That is, if the elastic yarn too much extended is applied to the diaper in order to prevent the liquid discharge from leaking outside, it can increase the tightness of the elastic yarn, but lead to uncomfortable wearing, and causing red mark and pain on the skin. On the other hand, if an elastic yarn relatively less extended is applied to the diaper, the wearing comfort would be improved, but causing a problem of leaking. Therefore, in order to improve both the functionality and wearing comfort, an elastic yarn is required to be flexible enough to extend easily when being pulled, and to be closely attached to the body all the time. This relates closely to power retention of an elastic yarn.
Among the conventional elastic yarns, a rubber-based elastic yarn has the best functionality and wearing comfort. A rubber-based elastic yarn has high power retention of 70% to 80% so that it has better wearing comfort and functionality than any other elastic yarns used before. It has drawbacks, however, in that the process quality is relatively inferior to that of a spandex fiber due to a yarn cutting during the production of diapers, and has a poor tolerance to chemicals. In terms of economic feasibility, the price per unit weight of rubber-based elastic yarn is lower compared to a spandex fiber, but in effect, the amount of rubber-based elastic yarn used to make one diaper is more than three times that of a spandex fiber, so in practice when making one diaper, using a rubber-based elastic yarn is less economical than using a spandex fiber.
Meanwhile, most of the dry spun spandex fibers used in disposable hygiene articles such as diapers or sanitary napkins are unable to achieve both the wearing comfort and functionality at the same time, since they have power retention of less than 65%. That is, in case that an elastic yarn is applied loosely to improve wearing comfort, the possibility of leakage of liquid discharge increases, while an elastic yarn is applied tightly in order not to cause leakage, the tightness is such great that it leads to red mark on the skin.
Furthermore, dry spun spandex fibers are potentially harmful and might cause skin irritation due to remaining solvents which are used in the preparation process and cannot be completely removed from the resulting fiber. In the recent public consultation (RCOM, 2012), the average DMAc residues reported herein for raw fibers (0.1-0.5%) were basically confirmed. This is disadvantageous for hygiene articles which come in direct contact with the skin, in particular when used for babies.
Therefore, it was an object of the present invention to provide hygiene articles which avoid the use of potentially harmful dry spun spandex fibers. At the same time it was desirable to obtain hygiene articles which have similar properties to those prepared using dry spun spandex fibers or rubber-based fibers.
Another object of the present invention was to provide disposable hygiene articles which can be prepared in an efficient manner.
These objects of the invention are achieved by a disposable hygiene article comprising a melt-spun elastic fiber.